Situ recovery of oil from tar sands using oil-external micellar dispersions

ABSTRACT

Hydrocarbon from sub-surface tar sands having an injection means in fluid communication with a production means is recovered by first heating the tar sands, then injecting an oil-external micellar dispersion into the tar sands and displacing it towards the production means to recover hydrocarbon through the production means. The tar sands are heated to a temperature sufficiently high to cause the incoming micellar dispersion to become heated to a temperature above 100*F by the time it travels about 7.5-15 feet into the tar sands. The micellar dispersion can be preceded by a slug of hot water, above 100*F., and the water can have a pH greater than about 7. Also, the water within the micellar dispersion can have a pH of about 7-14 and, preferably the dispersion is at a temperature up to about 100*F. The micellar dispersion contains hydrocarbon, surfactant, aqueous medium, and optionally cosurfactant and/or electrolyte.

[ *Apr. 2, 1974 SITU RECOVERY OF OIL FROM TAR SANDS USING OIL-EXTERNAL MICELLAR DISPERSIONS Inventors: Joe T. Kelly, deceased, late of Littleton, C010. by La Verne S.

Kelly, executrix; Fred H. Poettmann, Littleton, Colo.

Assignee: Marathon Oil Company, Findlay,

Ohio

Notice: The portion of the term of this patent subsequent to Mar. 14, 1989, has been disclaimed.

Filed: May 28, 1971 App]. No.: 148,120

Related US. Application Data Elkins 166/271 WTIIso IiTJL; Jack Ilfl-lum niel 3,392,105 7/1968 Poettmann 166/272 X 3,504,744 4/1970 Davis 166/274 X 3,221,813 12/1965 Closmann 166/273 X 3,375,870 4/1968 Salter 166/272 X Primary Examiner-Robert L. Wolfe Attorney, Agent, or in}; .loe C. liming; Richard [57] ABSTRACT Hydrocarbon from sub-surface tar sands having an injection means in fluid communication with a production means is recovered by first heating the tar sands, then injecting an oil-extemal micellar dispersion into the tar sands and displacing it towards the production means to recover hydrocarbon through the production means. The tar sands are heated to a temperature sufficiently high to cause the incoming micellar dispersion to become heated to a temperature above 100F by the time it travels about 75-15 feet into the tar sands. The micellar dispersion can be preceded by a slug of hot water, above 100F., and the water can have a pH greater than about 7. Also, the water within the micellar dispersion can have a pH of about 7-14 and, preferably the dispersion is at a temperature up to about 100F. The micellar dispersion contains hydrocarbon, surfactant, aqueous medium, and optionally cosurfactant and/or electrolyte.

20 Claims, No Drawings SITU RECOVERY OF OIL FROM TAR SANDS USING OIL-EXTERNAL MICELLAR DISPERSIONS CROSS REFERENCE TO RELATED APPLICATIONS This is a continuation-in-part of U. S. Ser. No. 888,898, filed Dec. 29, 1969, now U.S. Pat. No. 3,648,771.

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention related to the recovery of hydrocarbon from tar sands by an in situ process using an oilexternal micellar dispersion. The tar sands are first heated, then the micellar dispersion (contains hydrocarbon, surfactant and aqueous medium) is injected and displaced through the tar sand formation.

2. Description of the Prior Art 7 Tar sands, also known as oil sands and bituminous sands, are sands that contain a very viscous hydrocarbon. One of the largest deposits is the Athabasca sands found in Northern Alberta, Canada. These sands have an asphaltic appearance due to the viscous hydrocarbon. In general tar sands contain a very viscous oil or hydrocarbon which is substantially more viscous than the average crude oil found in subterranean formations, including low API" gravity crude oil.

' It is known in the prior art that oil from tar sands can be recovered by first flooding with steam and then flooding with a solution containing sodium hydroxide. The sodium hydroxide aids in emulsification of the viscous oil.

U. S. Pat. No. 2,882,973 to Doscher et a1 teaches in situ recovery of oil from tarsands using an aqueous solution containing substituents such as ether and/or ester groups. The nonionic surfactant is present in sufficient concentration to effect instantaneous emulsification of the oil and to maintain the oil in the emulsified state. Concentrations of 0. 1% by weight are effective for this purpose. The high pH is obtained using alkali metal hydroxide or ammonia.

U. S. Pat. No. 3,375,870 to Satter et al teaches an in situ process for recovering hydrocarbon from tar sands by heating the tar sands to a temperature about 300F., then using recognized recovery methods to recover the hydrocarbon. Examples of such processes are waterflooding, steam injection, forward combustion and gas injection.

Also, in situ combustion methods are useful to recover oil from oil sands. The fire front distills the oil ahead of it and the coke deposited by the destructive distillation is the major source for the combustion. The heat, the diluting action of the distillate forms, and the drive of the combustion gases all act to move the viscous hydrocarbon toward a production well in fluid communication with the combustion process.

SUMMARY OF THE INVENTION Applicants have discovered a novel method of recovering oil from tar sands by injecting an oil-extemal micellar dispersion into the tar sand reservoir and displacing it toward a production means in fluid communication with the tar sands. Before the micellar dispersion is injected, the reservoir is heated to a sufficient temperature to cause the incoming micellar dispersion to become heated to a temperature above 100F. by the time it travels about -15 feet into the reservoir. The oil-external micellar dispersion contains hydrocarbon, surfactant, and aqueous medium and optionally cosurfactant and/or electrolyte. The water within the dispersion can have a pH of about 7-14. Also, the micellar dispersion can be preceded by a hot water flood (i.e. temperature above 100F) the water flood can optionally be at a pH greater than 7. In addition, the micellar dispersion can be followed by a mobility buffer and this, in turn, followed by a drive material, e.g. water or hydrocarbon. The mobility buffer acts to impart a more stable flow to the process.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The oil-external micellar dispersion is comprised of hydrocarbon, surfactant, and aqueous medium. Optionally, alcohol and/or electrolyte can be incorporated. Examples of volume amounts include about 4% to about 50% hydrocarbon, about 5% to about aqueous medium, at least about 4% surfactant, about 0.01 to about 20% cosurfactant, and about 0.001% to about 5% by weight of electrolyte. In addition, the dispersion can contain other additives such as corrosion inhibiting agents, bactericides, sequestering agents, etc.

Examples of useful hydrocarbons include crude oil, partially refined fractions of crude oil, e.g. side cuts from crude columns, crude column overheads, gas oils, kerosenes, heavy naphthas, naphthas, straight-run gasoline, liquefied petroleum gases, etc.; and refined fractions of crude oil including propane, pentane, decane, dodecane, aryl compounds such as benzene, naphthalene, anthracene, and substituted products thereof. Also, the hydrocarbon can be a synthesized hydrocarbon. In addition, the unsulfonated hydrocarbon in petroleum sulfonates is useful as the hydrocarbon.

The aqueous medium can be soft, brackish, or brine water. Preferably, the water is soft but it can contain salts which are compatible with the ions within the tar sands.

The surfactant can be anionic, cationic or nonionic. Examples of useful surfactants include those found in U.S. Pat. No. 3,254,714 to Gogarty et a1. Especially useful surfactants are the petroleum sulfonates, also known as alkyl aryl naphthenic sulfonates. Preferred petroleum sulfonates include those having an average equivalent weight of about 350 to about 520 and more preferably about 400 to about 460. The sulfonate is preferably one containing a monovalent cation. Mixtures of different surfactants as well as mixtures of high, medium, and low average equivalent weight surfactants are useful. I

The cosurfactant (also known as semi-polar organic compound and cosolubilizer) can have different degrees of water solubility. Preferably, the water solubility of the cosurfactant is about 0.1% to about 20% or more and more preferably about 1% to about 5% at ambient temperature. Examples of useful cosurfactants include alcohols, amines, esters, aldehydes, ketones and like compounds containing 1 to about 20 or more carbon atoms and more preferably about 3-16 carbon atoms. Specific examples of useful alcohols include isopropanol, nand isobutanol, the amyl alcohols such as n-amyl alcohol, 1- and 2-hexanol, 1- and 2-octanol, decyl alcohols, alkaryl alcohols, alcoholic liquors such as fusel oil, etc. The alcohols can be primary, secondary, and tertiary alcohols. Preferably, concentrations of about 0.01% to about 5% by volume are useful and more preferably about 0.1% to about 3%. Mixtures of two or more different cosurfactants are useful.

The electrolyte useful in the oil-external micellar dispersions include inorganic bases, inorganic acids, and inorganic salts, organic bases, organic acids, and organic salts, which are either weakly or strongly ionized. Preferably the electrolytes are inorganic bases, inorganic acids, and inorganics salts, e.g. sodium hydroxide, sodium chloride, sodium sulfate, hydrochloric acid, sulfuric acid, sodium nitrate, ammonium hydroxide, etc. Examples of other useful electrolyes are found in U.S. Pat. No. 3,330,343. Preferably, the electrolyte is one that will yield a high pH, e.g. sodium hydroxide and like materials.

Specific examples of useful micellar dispersions include those taught in U. S. Pat. No. 3,497,006 to Jones and U.S. Pat. No. 3,254,714 to Gogarty et al.

Preferably the pH of the water within the micellar dispersion is within the range of about 7-14 and more preferably about 12. The desired pH can be obtained by adding the appropriate electrolyte, e.g. NaOH, NH4OH, etC. I

The temperature of the micellar dispersion is preferably above ambient temperature and less than about 100F. This can be effected by heating the micellar dispersion with conventional processing equipment. Also, high temperatures due to subterranean conditions can be utilized to heat the micellar dispersion as it progresses down the well bore.

The components of the dispersion are preferably designed to obtain a stable dispersion at the high temperatures of the preheated tar sand formation. This can be effected, e.g. by increasing the aromaticity of the hydrocarbon, increasing the electrolyte content, increasing the molecular weight of the surfactant and/or alcohol, etc. Specific methods to obtain thermostability ranges at higher temperatures are taught in US. Pat. No. 3,393,048 to Jones, U.S. Pat. No. 3,393,047 to Davis et al, US. Pat. No. 3,495,660 to Davis et al; US. Pat. No. 3,500,912 to Davis et al, and U.S. Pat. No. 3,508,61 l to Davis et al. The mixture of micellar dispersion components may be unstable at ambient temperature where the design temperature is substantially higher than ambient; however, this is not detrimental to the process since the mixture will be a stable micellar dispersion at the temperature within the reservoir.

The oil-external micellar dispersion can be preceded by a water slug at a temperature greater than 100F and more preferably greater than about 150F. Also, the pH of the water slug can be within the range of about 7-14.

Higher pHs are useful to aid in the emulsification of the oil from the tar sands. The high pH can be obtained by adding water-soluble bases, e.g. NaOH, NH OH, etc., to the aqueous preslug. Also, steam can be substituted for the hot water slug. Formation pore volumes of the aqueous preslug up to about 1 pore volume and greater are useful.

The effective mobility of the micellar dispersion flowing in the tar sands can be decreased to give a more stable fluid flow to reduce or inhibit fingering. Such can be obtained by adjusting the components within the micellar dispersion to obtain a desired viscosity.

The micellar dispersion can be followed by a drive material. Optionally, a mobility buffer can be injected behind the micellar dispersion and this, in turn, followed by a drive material. Examples of useful mobility buffers include aqueous and nonaqueous fluids containing mobility reducing agents such as high molecular weight, partially hydrolyzed polyacrylamides, polysaccharides, polyisobutylenes, etc. Any mobility reducing agent is useful as long as it is compatible with the tar sands and effectively reduces the mobility of the aqueous or nonaqueous mobility buffer slug. The mobility buffer reduces the tendency of the drive material to finger into the micellar dispersion.

As mentioned previously, the micellar dispersion can be followed by a drive material. The drive material can be aqueous or nonaqueous and can be liquid, gas or a combination of the two, e.g. steam. Preferably, it is an aqueous drive material. The drive material can contain ions, but the ions are preferably compatible with the ions within the subterranean formation.

Formation pore volume amounts of about 1% to about 30% or more of the oil-external micellar dispersion are useful with this invention. More preferably, about 1% to about 10% formation pore volume is useful. The mobility buffer can be present in amounts of about less than 5% to about 75% or more formation pore volume.

It is not intended that the invention be limited by the specifics taught above. Rather, all equivalents obvious to those skilled in the art are intendedto be included within the scope of the invention as defined within the specification and appended claims.

EXAMPLE 1 This example is presented to show specific examples of micellar dispersions useful with this invention. These examples are prepared at room temperature with minimal agitation. The compositions of the micellar dispersions are indicated in Table I:

TABLE I Surfactant Hydrocarbon Aqueous Medium Cosurfactant Sam- Per- Per- Per- 1111.] pie cent Type cent Type cent Type 100 ml. Type A- 5. 2 Ammonium petroleum sullonate 607 Henry plant water 0. 08 n-arnyl alcohol (avergae EqW=440,81% active). 75 Crude 70 {40% Palestine water 4 0.25 isopropanol. B-.. 10 Pyronate 20 d0 gg g g xgggi izzi 3.25 n-Hexanol.

1o Petronate L" 20- Straight-run gaso1ine 70 {Egg ggfi g gg gff 4.25 n-Amyl alcohol. D- 20 "Duponol WAQE 70 Distilled water 14 i-Amyl alcohol. E 10 Energetic W100 70 do 8.5 Do. F--." 10 Triton X-100 70 d0 5.5 Do. G 20 Arquad 12-50 70 do 17.0 Do. H 16.6 Solhbm pegrolegrn Stlillli0)l18.t6 (avg. 66.6 do 1.3 Isopropanol.

I 10 Ammonium petroleum sulfonate 60% Palestine water (avg. EqW =440, 81% active). 5 Crude on 85 {40% Henry plant water 5 n Amy] alcohol L (Zsnfl esq Surfactant Hydrocarbon Aqueous Medium Cosuriactant Sam- Per- Per- Per- 1111.]

ple cent Type cent Type cent Type 100 ml. Type I 7.4 Sulfonate defined inEiramp1e H... 49.6 Straight-run gasoline. 43 wat'ior'iianimg 500 ppm; huff": WWW '7 '7 a" dissolved solids.

K 11.6 60.6 .d0 24 Water definedin Example] 3.8% isopropanol. L 12.6 do 51.0. Pentane 33 do 3.4%isopropanol.

1 Pyronate 50, a sodium petroleum sulionate, average equivalent weight350. Sold by Sonneborn Chemical C0,, 300 Park Avenue South, New York,

New York 10010.

2 Petroiiate L, a sodium petroleum sulionate, average equivalent weight 422. Sold by Sonneborn Chemical 00., 300 Park Avenue South, New York, New York 10010.

3 Henry plant water is obtained from the Henry lease in Illinois; contains about 18,000 p.p.m. of dissolved salts.

4 Palestine water is obtained from the Palestine water reservoir in Palestine, Illinois; contains about 420 p.p.m. of dissolved salts.

N oTiL-Tho amount of cosurfactant is based on ml. of cosurfactant per 100 ml. of liquid containing surfactant, hydrocarbon and aqueous medium- 0 0pt in exemple K and L wherein the amount of alcohol is based on percent of the total volume of dispersions.

What is claimed is: micellar dispersion travels about 7.5 to about 15 1. A process of recovering hydrocarbon from subfeet into the tar sands, surface tar sands having at least one injection means in 2. injecting about 1% to about 30% formation pore fluid communication with at least one production volume Of the oil-external micellar dispersion intO means, comprising heating the tar sands to a temperathe tar sands, ture sufficient to heat an incoming oil-external micellar 3. thereafter, injecting about 5% to about 75% fordispersion to a temperature above about 100F. by the on p r v lume of a mobility buffer into the time the micellar dispersion travels about 7.5 to about tar Sands. 15 feet into the tar sands, injecting the oil-external miand injecting Sufficient drive material 0 cellar dispersion into the tar sands and displacing the Place the micellar dispersion and mobility buffer micellar dispersion toward at least one of the productoward the Production means and recovering Oil tion means and recovering hydrocarbon through said through the Prodlletion means.

1 1. The process of claim 10 wherein the micellar disproduction means.

persion 18 at a temperature above about ambient tem- 2. The process of claim 1 wherein the water phase within the micellar dispersion has a pH within the range Pel'ature and less than about f about 7 to about 14 12. The process of claim 10 wherein up to about 3. The process of claim 1 wherein a slug of hot water 100% formation P Volume of ah aqueous preslug at a temperature greater than 100F is injected into the tar sands before the micellar dispersion is injected.

13. The process of claim 12 wherein the pH of the aqueous preslug is about 7 to about 14.

14. The process of claim 10 wherein the micellar dispersion is comprised of hydrocarbon, surfactant, and aqueous medium.

15. The process of claim 14 wherein the micellar dispersion contains cosurfactant and/or electrolyte.

16. The process of claim 14 wherein the surfactant is petroleum sulfonate.

17. The process of claim 10 wherein the mobility buffer is an aqueous solution containing a mobility reducing agent.

18. The process of claim 10 wherein the drive mateat a temperature above 100F. is injected into the sands before the micellar dispersion is injected.

4. The process of claim 3 wherein the pH of the water is above about 7.

5. The process of claim 1 wherein the micellar dispersion is comprised of hydrocarbon, surfactant, and aqueous medium.

6. The process of claim 5 wherein the micellar disper- 4O sion contains cosurfactant and/or electrolyte.

7. The process of claim 1 wherein steam is injected into the tar sands to heat the tar sands before the micellar dispersion is injected.

8. The process of claim 1 wherein a mobility buffer is injected after the micellar dispersion.

9. The process of claim 1 wherein an aqueous drive material is injected to displace the micellar dispersion 15 aqueous" toward the production means 19. The process of claim 10 wherein steam is injected 10. A process of re o i h d b f bto heat the tar sands before the micellar dispersion is surface tar sands having at least one injection means in injected. fluid communication with at least one production 20. The process of claim 10 wherein the water phase means, Comprising! within the micellar dispersion has a pH of about 7 to l. heating the tar sands to a temperature sufficient to about 14 heat an incoming oil-external micellar dispersion to a temperature above about 100F. by the time the 

2. injecting about 1% to about 30% formation pore volume of the oil-external micellar dispersion into the tar sands,
 2. The process of claim 1 wherein the water phase within the micellar dispersion has a pH within the range of about 7 to about
 14. 3. The process of claim 1 wherein a slug of hot water at a temperature above 100*F. is injected into the sands before the micellar dispersion is injected.
 3. thereafter, injecting about 5% to about 75% formation pore volume of a mobility buffer into the tar sands,
 4. and then injecting sufficient drive material to displace the micellar dispersion and mobility buffer toward the production means and recovering oil through the production means.
 4. The process of claim 3 wherein the pH of the water is above about
 7. 5. The process of claim 1 wherein the micellar dispersion is comprised of hydrocarbon, surfactant, and aqueous medium.
 6. The process of claim 5 wherein the micellar dispersion contains cosurfactant and/or electrolyte.
 7. The process of claim 1 wherein steam is injected into the tar sands to heat the tar sands before the micellar dispersion is injected.
 7. ALSO, THE WATER WITHIN THE MICELLAR DISPERSION CAN HAVE A PH OF ABOUT 7-14 AND, PREFERABLY THE DISPERSION IS AT A TEMPERATURE UP TO ABOUT 100:F. THE MICELLAR DISPERSION CONTAINS HYDROCARBON, SURFACTANT, AQUEOUS MEDIUM, AND OPTIONALLY COSURFACTANT AND/OR ELECTROLYTE.
 8. The process of claim 1 wherein a mobility buffer is injected after the micellar dispersion.
 9. The process of claim 1 wherein an aqueous drive material is injected to displace the micellar dispersion toward the production means.
 10. A process of recovering hydrocarbon from sub-surface tar sands having at least one injection means in fluid communication with at least one production means, comprising:
 11. The process of claim 10 wherein the micellar dispersion is at a temperature above about ambient temperature and less than about 100*F.
 12. The process of claim 10 wherein up to about 100% formation pore volume of an aqueous preslug at a temperature greater than 100*F is injected into the tar sands before the micellar dispersion is injected.
 13. The process of claim 12 wherein the pH of the aqueous preslug is about 7 to about
 14. 14. The process of claim 10 wherein the micellar dispersion is comprised of hydrocarbon, surfactant, and aqueous medium.
 15. The process of claim 14 wherein the micellar dispersion contains cosurfactant and/or electrolyte.
 16. The process of claim 14 wherein the surfactant is petroleum sulfonate.
 17. The process of claim 10 wherein the mobility buffer is an aqueous solution containing a mobility reducing agent.
 18. The process of claim 10 wherein the drive material is aqueous.
 19. The process of claim 10 wherein steam is injected to heat the tar sands before the micellar dispersion is injected.
 20. The process of claim 10 wherein the water phase within the micellar dispersion has a pH of about 7 to about
 14. 